401k.loans MCP

This server provides AI assistants with read-only access to 401(k) loan calculators, enabling users to estimate payment costs, compare loan options against withdrawals or HELOCs, and calculate early withdrawal taxes and penalties based on IRS rules and current rates.

Visit 401k.loans

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Vendor evidenceStreamable HTTPNo sign-inEndpoint checked 2026-11-01Operated by 401k.loans

MCP endpoint (Streamable HTTP)

https://401k.loans/mcp

Vendor documentation

What you can do with it

Calculate the true cost of a 401(k) loan including lost growth and taxes
Compare 401(k) loans against hardship withdrawals, personal loans, and HELOCs
Estimate income tax and penalties for early 401(k) withdrawals

Source and maintenance

Vendor evidenceRegistry 1.2026.1101.1

mcp-registry: loans.401k/401k-loans@1.2026.1101.1 Project website

Protocol and capabilities

Server: 401k-loans 1.0.0
MCP protocol: 2025-06-18
Tools: 3 advertised
Resources: Not advertised
Resource templates: Not advertised
Prompts: Not advertised

Server-advertised capabilities

{
  "tools": {
    "listChanged": false
  }
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

401k.loans runs calculators for the cost of borrowing from or withdrawing from a 401(k). These tools run the same arithmetic as the calculators on the site (same formulas, same defaults) on the numbers you pass. calculate_401k_loan_cost: payment, interest, growth gap and the leaving-your-job bill for a plan loan. compare_401k_loan_alternatives: the same cash raised four ways (401(k) loan, hardship withdrawal, personal loan, HELOC). calculate_401k_early_withdrawal: tax, the 10% additional tax and withholding on a withdrawal. Rules come from the Internal Revenue Code (72(p) loan limits and 5-year term, 72(t) 10% additional tax, 402(c)(3)(C) loan offset rollover deadline) and 2026 federal brackets (Rev. Proc. 2025-32). Prefilled rates: plan loan = prime + 1 point as an example (Federal Reserve H.15 prime, October 21, 2026 at build, newer when the live feed has one); personal loan = Federal Reserve G.19 commercial bank 24-month average (Q3 2026); HELOC = prime alone. Every source with its date: https://401k.loans/sources/ Results are estimates from the inputs given, using a flat marginal tax rate and an assumed return. They are not tax, legal or investment advice, not a loan quote, and not a statement of any particular plan's terms; a plan sets its own rate, fees and limits within the law. Ask the user for their vested balance, plan rate and tax bracket when they can give them.

Tools

3 advertised

calculate_401k_loan_cost — True cost of a 401(k) loan

Advertised by the server during the last successful anonymous check.

Advertised read-only

Runs the 401k.loans true-cost calculator: payment per paycheck and number of payments, total repaid and interest, pre-tax pay needed per payment, tax later on the interest, the 401(k) balance at payoff with and without the loan (growth gap) and that gap at 65, the legal and usual plan borrowing limits, and, if you might leave the job, the balance owed then plus the tax and 10% additional tax if it is not repaid or rolled over.

calculate_401k_loan_cost input schema

{
  "type": "object",
  "required": [
    "vested_balance",
    "loan_amount"
  ],
  "properties": {
    "age": {
      "type": "number",
      "default": 40,
      "maximum": 80,
      "minimum": 18,
      "description": "Your age today, 18 to 80. Default 40."
    },
    "years": {
      "enum": [
        1,
        2,
        3,
        4,
        5,
        10,
        15
      ],
      "type": "integer",
      "default": 5,
      "description": "Years to repay: 1 to 5, or 10 or 15 for a loan to buy your main home. Default 5."
    },
    "loan_amount": {
      "type": "number",
      "maximum": 100000000,
      "minimum": 1,
      "description": "Amount to borrow in dollars, e.g. 15000."
    },
    "pay_frequency": {
      "enum": [
        "weekly",
        "biweekly",
        "semimonthly",
        "monthly"
      ],
      "type": "string",
      "default": "biweekly",
      "description": "How often you are paid (one loan payment per paycheck). Default biweekly."
    },
    "plan_rate_pct": {
      "type": "number",
      "maximum": 20,
      "minimum": 0,
      "description": "Plan loan interest rate in percent, 0 to 20. Default: the prime rate plus 1 point, as an example; the real rate is on your plan's loan paperwork."
    },
    "state_tax_pct": {
      "type": "number",
      "default": 0,
      "maximum": 15,
      "minimum": 0,
      "description": "State income tax rate in percent, 0 to 15. Default 0."
    },
    "vested_balance": {
      "type": "number",
      "maximum": 100000000,
      "minimum": 1,
      "description": "Vested 401(k) balance in dollars, e.g. 60000."
    },
    "assumed_return_pct": {
      "type": "number",
      "default": 6,
      "maximum": 20,
      "minimum": -20,
      "description": "Annual return you assume the 401(k) would earn, in percent (-20 to 20). An assumption, not a forecast. Default 6."
    },
    "federal_bracket_pct": {
      "enum": [
        10,
        12,
        22,
        24,
        32,
        35,
        37
      ],
      "type": "integer",
      "default": 22,
      "description": "2026 federal income tax bracket in percent (Rev. Proc. 2025-32): 10, 12, 22, 24, 32, 35 or 37."
    },
    "leave_job_after_months": {
      "enum": [
        0,
        6,
        12,
        18,
        24,
        36,
        48
      ],
      "type": "integer",
      "default": 24,
      "description": "Model leaving the job after this many months (0 = do not model it). Default 24, as on the page."
    },
    "lost_match_per_paycheck": {
      "type": "number",
      "default": 0,
      "maximum": 100000,
      "minimum": 0,
      "description": "Employer match you would lose with them, dollars per paycheck. Default 0."
    },
    "paused_contribution_per_paycheck": {
      "type": "number",
      "default": 0,
      "maximum": 100000,
      "minimum": 0,
      "description": "Your own 401(k) contributions you would stop while repaying, dollars per paycheck. Default 0."
    }
  },
  "additionalProperties": false
}

calculate_401k_loan_cost annotations

{
  "title": "True cost of a 401(k) loan",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

compare_401k_loan_alternatives — Compare a 401(k) loan with a hardship withdrawal, personal loan and HELOC

Advertised by the server during the last successful anonymous check.

Advertised read-only

Prices four ways to raise the same cash with the 401k.loans comparison tool: 401(k) loan, hardship withdrawal (grossed up for tax and the 10% additional tax), personal loan (rate plus origination fee) and HELOC. For each: amount taken out, monthly payment, money gone for good (interest to others, fees, tax, penalty), interest paid back to yourself, how much smaller the 401(k) is at term end and at 65, and whether it is allowed.

compare_401k_loan_alternatives input schema

{
  "type": "object",
  "required": [
    "cash_needed",
    "vested_balance"
  ],
  "properties": {
    "age": {
      "type": "number",
      "default": 40,
      "maximum": 80,
      "minimum": 18,
      "description": "Your age today, 18 to 80. Default 40."
    },
    "years": {
      "enum": [
        1,
        2,
        3,
        4,
        5
      ],
      "type": "integer",
      "default": 3,
      "description": "Years to pay back, 1 to 5. Default 3."
    },
    "cash_needed": {
      "type": "number",
      "maximum": 100000000,
      "minimum": 1,
      "description": "Cash you need in hand, in dollars, e.g. 10000."
    },
    "plan_loan_fee": {
      "type": "number",
      "default": 0,
      "maximum": 10000,
      "minimum": 0,
      "description": "Flat 401(k) loan fee in dollars. Default 0."
    },
    "plan_rate_pct": {
      "type": "number",
      "maximum": 20,
      "minimum": 0,
      "description": "401(k) plan loan rate in percent, 0 to 20. Default: the prime rate plus 1 point, as an example."
    },
    "state_tax_pct": {
      "type": "number",
      "default": 0,
      "maximum": 15,
      "minimum": 0,
      "description": "State income tax rate in percent, 0 to 15. Default 0."
    },
    "heloc_rate_pct": {
      "type": "number",
      "maximum": 20,
      "minimum": 0,
      "description": "HELOC rate in percent, 0 to 20. Default: the prime rate alone, before the margin a lender adds."
    },
    "vested_balance": {
      "type": "number",
      "maximum": 100000000,
      "minimum": 0,
      "description": "Vested 401(k) balance in dollars, e.g. 60000."
    },
    "penalty_exception": {
      "type": "boolean",
      "default": false,
      "description": "true if an exception to the 10% early withdrawal tax applies (for example, you left this employer in or after the year you turned 55). The 10% is never applied at 59.5 or older. Default false."
    },
    "assumed_return_pct": {
      "type": "number",
      "default": 6,
      "maximum": 20,
      "minimum": -20,
      "description": "Annual return you assume the 401(k) would earn, in percent (-20 to 20). An assumption, not a forecast. Default 6."
    },
    "federal_bracket_pct": {
      "enum": [
        10,
        12,
        22,
        24,
        32,
        35,
        37
      ],
      "type": "integer",
      "default": 22,
      "description": "2026 federal income tax bracket in percent (Rev. Proc. 2025-32): 10, 12, 22, 24, 32, 35 or 37."
    },
    "heloc_closing_costs": {
      "type": "number",
      "default": 0,
      "maximum": 100000,
      "minimum": 0,
      "description": "HELOC closing costs in dollars. Default 0."
    },
    "origination_fee_pct": {
      "type": "number",
      "default": 0,
      "maximum": 12,
      "minimum": 0,
      "description": "Personal loan origination fee in percent of the loan, 0 to 12. Default 0."
    },
    "personal_loan_rate_pct": {
      "type": "number",
      "maximum": 36,
      "minimum": 0,
      "description": "Personal loan interest rate in percent (not the APR), 0 to 36. Default 11.9, the Federal Reserve G.19 average on 24-month bank loans (Q3 2026)."
    }
  },
  "additionalProperties": false
}

compare_401k_loan_alternatives annotations

{
  "title": "Compare a 401(k) loan with a hardship withdrawal, personal loan and HELOC",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

calculate_401k_early_withdrawal — 401(k) early withdrawal tax and penalty

Advertised by the server during the last successful anonymous check.

Advertised read-only

Runs the 401k.loans early withdrawal calculator for a cash-out or hardship withdrawal: amount taken out (or the gross needed to net a target), income tax at your marginal rates, the 10% additional tax, what you keep, what the plan withholds up front (20% mandatory, or 10% default for hardship), the check amount, and the balance due or refund at filing.

calculate_401k_early_withdrawal input schema

{
  "type": "object",
  "required": [
    "amount"
  ],
  "properties": {
    "mode": {
      "enum": [
        "gross",
        "net"
      ],
      "type": "string",
      "default": "gross",
      "description": "\"gross\" = amount is what you take out of the plan; \"net\" = amount is what you need in hand after tax. Default gross."
    },
    "amount": {
      "type": "number",
      "maximum": 100000000,
      "minimum": 1,
      "description": "Dollar amount, e.g. 20000. See mode."
    },
    "hardship": {
      "type": "boolean",
      "default": false,
      "description": "true for a hardship withdrawal (10% default withholding instead of the 20% that applies to most other withdrawals). Default false."
    },
    "state_tax_pct": {
      "type": "number",
      "default": 0,
      "maximum": 15,
      "minimum": 0,
      "description": "State income tax rate in percent, 0 to 15. Default 0."
    },
    "federal_bracket_pct": {
      "enum": [
        10,
        12,
        22,
        24,
        32,
        35,
        37
      ],
      "type": "integer",
      "default": 22,
      "description": "2026 federal income tax bracket in percent (Rev. Proc. 2025-32): 10, 12, 22, 24, 32, 35 or 37."
    },
    "additional_10pct_tax_applies": {
      "type": "boolean",
      "default": true,
      "description": "true if you are under 59.5 and no exception applies, so the 10% additional tax is due. Default true."
    }
  },
  "additionalProperties": false
}

calculate_401k_early_withdrawal annotations

{
  "title": "401(k) early withdrawal tax and penalty",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks: 1 of 1 (100%)
Average latency: 417 ms
95th percentile latency: 417 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

Nov 1, 2026, 10:15 PM UTC · probe · passed · 417 ms · metadata changed · 3 tool(s)

Connect from your client

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This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http 401k-loans-mcp https://401k.loans/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add 401k-loans-mcp --url https://401k.loans/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable 401k-loans-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "401k-loans-mcp": {
      "url": "https://401k.loans/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).

Cline configuration

{
  "mcpServers": {
    "401k-loans-mcp": {
      "type": "streamableHttp",
      "url": "https://401k.loans/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start 401k-loans-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "401k-loans-mcp": {
      "type": "http",
      "url": "https://401k.loans/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http 401k-loans-mcp https://401k.loans/mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.

Claude Desktop configuration

{
  "mcpServers": {
    "401k-loans-mcp": {
      "url": "https://401k.loans/mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "401k-loans-mcp": {
      "serverUrl": "https://401k.loans/mcp"
    }
  }
}

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401k.loans MCP

Endpoint and access

What you can do with it

Source and maintenance

Protocol and capabilities

Server-provided instructions

Tools

Prompts

Resources

30-day availability

Maintenance history

Connect from your client

Claude Code

Codex

Cursor

Cline

VS Code

Gemini CLI

Claude Desktop

Windsurf

Let your agent find its tools

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